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The Atacama desert in South America has been in a super-dry state far longer than any other location on Earth - nearly 40 million years in some places.
The Atacama is well known for its lack of rainfall, but scientists are only now getting a handle on how long it has experienced low precipitation levels.
Dr Tibor Dunai from Edinburgh, UK, is working in the region to date surfaces. His team reports the existence of hyper-arid conditions in the desert have lasted at least 20 million years.
"If you camp there, even after five days, you will notice that there are no flies because there is nothing for them to eat; that's how dry it is," Dr Dunai told the BBC.
"The desert is known for saltpetre which was very important in explosives production in the past. It is the only place in the world where it has accumulated because it is so easily dissolved by rainfall."
There are locations in the Atacama where not a single drop of rain has been recorded by humans, and the Edinburgh University researcher has studied dry river beds he can show have had no water running through them for 120,000 years.
But it is with the general hyper-aridity conditions of the Atacama that the Scottish-based scientist is most interested. Hyper-arid zones can receive some moisture (less than a few tens of millimetres per year), although this can be delivered simply by fogs.
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